"Chronic Prostatitis": part 3

Anatomy and Physiology

To enable us to understand the possible mechanisms leading to "chronicprostatitis" we have to know some basic facts about the anatomy andphysiology of the prostate.

The prostate is a gland situated underneath the bladder(the bladder neck) and is perforated by the first portion ofthe urethra. The 2 ejaculatory ducts enter the upper part ofthe prostate from behind, travel through the gland and open into the urethra ona small protuberance (3-4 mm) of the urethral mucosa called theverumontanum ("veru"). The veru isvery critical because of the convergence of several other structures:

Between the 2 openings of the ejaculatory ducts, we find the opening of theutricle, a remnant of our early life as embryo (a small ductrepresenting the rests of the tissue which in the female develops into theuterus).Theappearance of the utricle can vary widely from a tiny dimple in the veru to along narrow duct extending deep into the prostatic tissue parallel to theejaculatory ducts in the midline. In some individuals, this duct obliteratesforming a cyst (utricular cyst) in the prostate, not rarely the cause ofsymptoms identical to those of "chronic prostatitis".

The prostate is composed of 25-30 small glandular units (acini)located in the periphery of the prostate, and each glandular unit is connectedto the outside world by a tiny duct which opens into the urethra at each side indirect proximity to the veru. The prostatic acini produce a fluid that, atorgasm, is expelled from the acini by contraction of the prostatic smooth muscletissue surrounding these acini. The composition of the prostatic fluid is vitalfor the well-being of the spermatic cells outside the body and severealteration, like in certain forms of chronic prostatitis, can degrade fertility.

Other important anatomical structures, mostly neglected in the literature,are the seminal vesicles (SV).Theseglands reside on the backside of the lower part of the bladder, their body(about 5-8 cm long, .6-1 cm wide) lies alongside the deferent duct (whichcarries the sperm cells from the testis to the urethra) and empties into thisduct before the deferent duct enters the prostate to become the ejaculatoryduct. The SVs are structurally hollow organs comparable to the gallbladder, butwith multiple small saccular compartments (looking almost like a grape)interconnected with each-other. The wall of the SVs is composed of an internalcellular lining (glandular cells) which produces a fluid necessary for theextracorporeal survival of the sperm cells. This fluid, together with the fluidfrom the prostatic acini, constitutes a major part of the volume of thespermatic fluid; only a small part comes from the testicles. The outsidemuscular shell of the SVs contracts and expells the secretion at orgasm.

In summary, in a minute spot of the prostatic urethra around the veru,covering an area not larger then 1 square cm (about 1/6 square inch) we find allthe openings where the spermatic secretion has to pass through. One can immaginethat a slight change (focal inflammation with edema, calcifications, microscarsafter inflammatory disease etc) can distort, compress, obstruct (partially orcompletely, temporarily or definitively) those tiny openings creating all theconditions necessary for disease in one, few or many prostatic glandularsubunits or the seminal tract. Of course, if passage through one or several ofthese ducts is not completely restored (e g due to inadequate treatment of anacute exacerbation of prostatitis, permanent changes like calcified deposits ofdetritus or scars) we'll have to expect chronification of the inflammatoryprocess (not always symptomatic) with acutisation from time to time. The closerelationship of the SVs and the prostate to the bladder neck and the trigone (anarea in the bladder floor adjacent to the bladder neck), the most sensitiveparts of the bladder with a dense concentration of sensory nerve endings,explain the occurrence of urgent desire to void frequently associated withirritative conditions in the prostate/SV. In conclusion, an comprehensiveappreciation of the anatomical structures and their relationship is necessaryfor the understanding of the different syndromes that run under the term of "chonicprostatitis", instead of a view limited to the prostate only.